1. Field of the Invention
The present invention relates to an method and apparatus for piecing, to a lap sheet from an almost exhausted, roll, the leading end of a lap sheet from a new lap roll. The present invention can be suitably used for a textile machine such as a comber or a ribbon lap machine.
2. Background of the Invention
U.S. Pat. No. 5,144,731 discloses an automatic lap sheet piecing apparatus. According to this prior art, a lap sheet from a new roll is placed on a pair of spaced feed rollers, and the leading end of the lap sheet is held against a suction pipe by suction. The sucked end of the new lap sheet is moved to a location above a tail end of an old lap sheet being fed to a spinning machine. Then, the suction is reduced, so that the leading end of the new lap sheet is placed on the broken end of the old lap sheet on a lap sheet plate. Then, the suction pipe (with no suction) is moved toward the lap plate to contact the superimposed portions of the lap sheets. The suction pipe is then moved horizontally, so that the two lap sheets are smoothed against each other to prevent the fibers at the superimposed ends of the old and new lap sheets from separating. In order to obtain the above-mentioned movement of the suction pipe, a supporting arm is provided, to which a rocking movement is applied from a first motor, and the supporting arm is, at its tip end, provided with a shaft, to which a rotational movement from a second motor is applied. Connected to an end of the shaft is a base end of a suction arm, which has a free end to which the suction pipe is connected.
Regarding the breakage of a tail end of a lap sheet being fed to a spinning machine, two kind of prior arts have heretofore been proposed. Namely, in U.S. Pat. No. 5,027,475, a set of carrier rolls is arrange upstream from a set of feed rollers, which cooperate with a swingable lap sheet roller for supporting a lap sheet fed to the spinning machine. When the lap roll fed to the spinning machine is nearly emptied, a swing movement of the lap roll is obtained, for causing the consumed lap roll to be exhausted to a trough, while the carrier roller are reversed for breaking the lap sheet at a location between the feed rollers and the carrier rollers. Then the lap sheet roller is swung to the upper position, which allows a full lap roll to be supported by the cooperation of the lap roll with the carrier rollers, which is followed by a piecing operation of the lap sheet from the full lap roll to the broken lap sheet to the spinning machine.
As for an alternative for the breakage of the tail end of a lap sheet, in a comber disclosed by the U.S. Pat. No. 2,559,074, an old lap sheet nearly emptied is dropped downwardly from a pair of feed rollers during the operation of the comber, while, in synchronous with the dropping of the consumed roll, a previously prepared full lap sheet on a bobbin is rested on the feed rollers. A comb is arranged below a feed roller, so that the comb cooperates with the lap from the consumed lap roll when it is dropped, which causes the lap sheet from the old lap roll to be broken.
U.S. Pat. No. 5,144,731 is disadvantageous in that the fibers are apt to be separated at the location where the end of the old lap sheet is superimposed with the end of the new lap sheet, which causes the quality of the pieced portion of the lap sheet to be reduced. In this patent, the superimposition of the ends of the old and new lap sheets is done by a horizontal movement of the suction nozzle. However, the smoothing operation thus obtained is insufficient to obtain the desired quality at the pieced portion. Furthermore, the movement of the suction pipe for the smoothing operation is obtained by the combined movements of different motors. Thus, a sophisticated control of the separate motors is required to obtain a movement of the pipe member so that the pipe member is uniformly pressed to the lap sheets to obtain a desired smoothing operation of the fibers.
Furthermore, the breaking operation of the end of the old lap roll in U.S. Pat. No. 5,027,475 is defective in that a provision for pressing the old lap roll is necessary, which causes the apparatus to be complicated. In the second prior art (U.S. Pat. No. 2,559,074), the breakage of the lap is done using the comb member acting with the lap sheet fed during the execution of the combing operation. Namely, the breakage of the lap can only be done when the combing machine is operated. In other words, breakage of the lap sheet can not be done when the combing machine is stopped.